Question

rights and duties are complementary to each other​

Answer 1

Answer:

Rights impose duties by definition.

A right just is an interest (or similar. Whilst interest theories of rights are prominent they’re not the only game in town) that is of sufficient importance to ground a duty in others. Typically, this duty is cashed out in some form of social protection. So a right to freedom of religion grounds a duty in others not to prevent you worshipping in the way you see fit, and this is cashed out in the courts and other agents of the state protecting religious conduct from various sorts of interference.

So asking why rights generate correlative duties doesn’t really make sense. If it doesn’t generate a correlative duty, it ain’t a right. Rights are only a part of the moral space.